US troops have raised the Stars and Stripes over Iwo Jima four days after landing on the Japanese-held volcanic island.

The 28th Regiment of the 5th Marine Division took Mount Suribachi at 1030 local time.

The extinct volcano offers a strategic vantage point for the ongoing battle for control of the island.

Lying in the north-west Pacific Ocean 650 miles (1,045 kms) from Tokyo, Iwo Jima would serve as a useful base for long-range fighters to cover B-29 Superfortresses in a bombing campaign against the Japan's capital.

Although the Stars and Stripes are flying over the island the battle is far from over and the Japanese are reported to be defending every inch of the island using elaborate underground defences.

The battle for Iwo Jima has been described as the toughest fight in US Marine history by the commander of the Marines in the Pacific, Lt-General M "Howling Mad" Smith.

On 19 February, after four days of naval and air bombardment had pounded the beaches and weakened Japanese defences, the 4th and 5th Marine Divisions landed on the south side of the island under the overall command of Vice-Admiral Richmond Kelly Turner.

After a day of little resistance, the enemy fought back in earnest.

Hidden in fortified caves and pillboxes linked by a series of tunnels they relentlessly attacked the Americans with artillery fire, grenades and other explosives as well as from the air.

The last 24 hours have seen the fiercest fighting yet with every step of the way up the mountain defended by the Japanese.

But by 1035 local time the Marines had reached the summit of Mt Suribachi.

Reporting from the US base in Guam, Admiral Chester W Nimitz said so far the battle had cost 5,372 casualties, including 644 dead, and that US carrier-based aircraft flying over the Bonin Islands north of Iwo Jima had destroyed three enemy planes.

Reuters news agency also reports Marines have finally reached the Japanese fighter-plane base in the centre of the island, which lies just 700 yards (640m) from the bomber airfield taken by the Americans two days ago.

The Japanese army and naval troops under Lt-General Kuribayashi Tadamichi fought to the death but the US Marines finally secured the whole island on 26 March in one of the bloodiest battles of the war.

Out of the 74,000 Marines that landed more than a third were killed or wounded.

The US then used the island to launch bombing raids on Japan.

The photograph of the US Marines raising the flag over Mount Suribachi was taken by Associated Press photographer Joe Rosenthal and is one of the most famous images of the war. It won the Pulitzer Prize in 1945.